Ultraviolet radiation lamps are widely utilized in many different industries for irradiating different substances with ultraviolet radiation. UV lamps are utilized to kill bacteria in food and water, and also on the packaging for food and beverage products. Ultraviolet irradiation lamps are utilized to treat food packaging products such as dairy product cartons, lids, sealing films, plastic wrap, labels, reusable product containers and other articles used in the packaging of products, as well as in the sanitization of food and beverages items themselves.
In conventional ultraviolet bacteria irradiation treatment a plurality of ultraviolet lamps are typically positioned within an enclosure through which the materials to be sanitized by UV irradiation are passed. As the material to be treated is advanced past the stationary ultraviolet lamps, either by fluid flow or by some apparatus for conveyance, the material to be treated passes in close proximity to the lamps. Ultraviolet radiation emitted by the lamps kills bacteria, microbes, and other harmful biological contaminants.
Because ultraviolet radiation is harmful to the human operators of the sanitizing equipment, it is important for the enclosures containing the ultraviolet radiation lamps to be shielded to prevent harmful UV radiation from being directed at the equipment operators and other individuals in the vicinity. UV radiation can be particularly damaging to a person's eyesight.
The most inexpensive type of shielding is some type of opaque substance, such as metal or thick plastic which resists penetration to both ultraviolet radiation and also visible light. As a consequence, the ultraviolet lamps that irradiate the materials to be treated are normally concealed from view and are not directly observable by the equipment operators. Shielding avoids exposure to harmful radiation, especially damage to the eyes of the equipment operators.
However, since it is typically not possible to observe the ultraviolet lamps in operation, a lamp can cease to emit ultraviolet radiation without being noticed by the equipment operators. If a nonfunctional ultraviolet lamp is left in position, material to be treated flows past it, but is not subjected to sufficient ultraviolet radiation. Consequently, while the equipment operators may think that the system is effectively performing its irradiation function, in fact, some of the material passing through the system may be untreated or treated inadequately.
To remedy this situation conventional electronic systems have been devised to display the operational status of ultraviolet radiation tubes to the equipment operators at a status display panel. In such systems electronic circuits are embodied in the ultraviolet lamp couplings through which power is provided to generate ultraviolet radiation. The electrical power utilized to produce the required ultraviolet radiation also serves to provide an operational status indication for each ultraviolet lamp to the equipment operators.
While such electronic status indicators do perform the desired function of displaying to the equipment operators the operational status of the different ultraviolet lamps, these circuits are unnecessarily complex and therefore expensive. Furthermore, these sensing circuits can malfunction and provide either false positive or false negative indications which disrupt the efficient throughput of materials to be treated.